The internet started as a US military project called ARPANET

The internet grew out of ARPANET, a 1969 US Department of Defense project designed to allow computers at different universities to share data. The first message ever sent over the network on 29 October 1969 was 'lo' — the system crashed before the sender could finish typing 'login'. By 1971 the network had 23 nodes; by 1990 it was opened to the public as the World Wide Web. The decentralised design — intended to survive a nuclear strike by routing around damaged nodes — is the same architecture that underlies the global internet today.

Source: Hafner & Lyon, Where Wizards Stay Up Late (1996)